海城小孤山的骨制品和装饰品

小孤山的骨制品包括鱼叉、标枪头和骨针,它们在工艺上与欧洲旧石器时代晚期、尤其是马格德林文化的制品十分相似。小孤山的骨针和山顶洞的骨针相似,但工艺水平稍高。小孤山的装饰品包括穿孔牙齿和蚌壳,它们与山顶洞的同类制品基本一致,但穿孔技术稍高。小孤山含上述制品的堆积物的时代为晚更新世,年代测定的初步结果为距今40,000—20,000年左右。     

Study of physiopathological phenomena in dental enamel by neutron activation analysis

An epithermal neutron activation method is used to determine the concentration of mineral elements in human dental enamel. A large number (252) of samples from ancient and modern origins are analyzed. The analytical results are mathematically processed using a statistical multivariant method. This allows to differentiate deciduous from permanent teeth and decayed from sound enamel. It is also possible to distinguish the teeth coming from two different necropoles. The origin and the localization of determined elements in the mineralized part, or in the aqueous-organic part, of enamel is suggested. Their role, as witnessed in the physiopathological phenomena of dental enamel, is discussed.     

Changes in the lower premolar-size sequence during hominid evolution. Physlogenetic implications

The size relationship between the crown area of the lower canines (Cs), third (P3s) and fourth premolars (P4s), and first molars (M1s) in hominids is examined by means of the regression analysis. The lower P3 seem to be under the influence of those factors that control both the size of the anterior and posterior teeth, and the P4:P3 size ratio is related to the relative size of the anterior and posterior dentitions. So, the P4>P3 sequence is associated with the megadontia and hipermegadontia of the posterior teeth, whereas the expansion of the anterior teeth produces the P3>P4 sequence. We consider the P4:P3 size ratio as an excellent indicator of the taxonomic and philogenetic status of fossil hominids.     

Occurrence of heavy metals,sodium, calcium,and potassium in human hair,teeth, and nails

Heavy metals in biological samples: nails, teeth, and hair were examined during 1991–1993. Investigations of biological samples (hairn=249 samples, teethn=145, nailsn=80 samples) were provided for inhabitants of selected towns in Beskid Śląski. The towns are small mountain towns in southern Poland: Wista, Szczyrk, Istebna, Koniaków, and Jaworzynka. The analysis of ANOVA and MANOVA variances were used for biological samples in the context of age, sex, and type of samples for 12 elements (Pb, Cd, Cr, Zn, Fe, Cu, Mn, Ni, Co, Ca, Na, and K). The matrix correlation and cluster analysis were applied to explain the behavior of metals in human hair, teeth, and nails.     

Four-million-year-Old hominids from East Lake Turkana,Kenya

A piece of mandible and several isolated teeth are reported from fluviatile sediments older than 4 million years at East Lake Turkana. They most closely resemble hominids from Laetoli, Tanzania and Hadar, Ethiopia which have been assigned to Australopithecus afarensis. © 1994 Wiley-Liss, Inc.     

Histological Techniques to Improve Testing of Pulpal Response of Teeth to Filling Material

Two fixation fluids, two fixation techniques and two embedding methods were investigated for their effects on the quality of sections of teeth for pulpal response to filling materials to improve evaluation of pulpal responses. Sections from 32 baboon teeth were prepared, half with experimental cavities and half without, using either 10% formaldehyde or 4% glutaraldehyde, longitudinal tooth splitting or removal of the tooth apex, and paraffin or K plast resin embedding; decalcification in a formic acid mixture was a constant throughout. Histometric analysis showed that paraffin embedding produced less shrinkage than the K Plast resin embedding although the difference was not statistically significant. Six parameters of separation at the pu1p:dentine interface were studied: embedding, fixative, presence or absence of a cavity, cutting technique and individual animal tooth type. Statistical investigation revealed that fixative, cutting technique, and fixative and cutting technique combined had significant influences on the separation artifact. Of the combinations tested the choice of embedding method depends on which of the two artifacts, shrinkage or separation, is more adverse in the opinion of the investigator. Four percent glutaraldehyde together with the longitudinal split technique of fixation. processed by either K Plast resin embedding or paraffin embedding produced satisfactory pulpal sections.     

Stem cells from human exfoliated deciduous teeth ameliorate concanavalin A-induced autoimmune hepatitis by protecting hepatocytes from apoptosis

BACKGROUNDAutoimmune hepatitis is a serious autoimmune liver disease that threatens human health worldwide, which emphasizes the urgent need to identify novel treatments. Stem cells from human exfoliated deciduous teeth (SHED), which are easy to obtain in a non-invasive manner, show pronounced proliferative and immunomodulatory capacities.AIMTo investigate the protective effects of SHED on concanavalin A (ConA)-induced hepatitis in mice, and to elucidate the associated regulatory mechanisms.METHODSWe used a ConA-induced acute hepatitis mouse model and an in vitro co-culture system to study the protective effects of SHED on ConA-induced autoimmune hepatitis, as well as the associated underlying mechanisms.RESULTSSHED infusion could prevent aberrant histopathological liver architecture caused by ConA-induced infiltration of CD3⁺, CD4⁺, tumor necrosis-alpha⁺, and interferon-gamma⁺ inflammatory cells. Alanine aminotransferase and aspartate aminotransferase were significantly elevated in hepatitis mice. SHED infusion could therefore block ConA-induced alanine aminotransferase and aspartate aminotransferase elevations. Mechanistically, ConA upregulated tumor necrosis-alpha and interferon-gamma expression, which was activated by the nuclear factor-kappa B pathway to induce hepatocyte apoptosis, resulting in acute liver injury. SHED administration protected hepatocytes from ConA-induced apoptosis. CONCLUSIONSHED alleviates ConA-induced acute liver injury via inhibition of hepatocyte apoptosis mediated by the nuclear factor-kappa B pathway. Our findings could provide a potential treatment strategy for hepatitis.